Containers with which the present invention is concerned are a practical and cheap way for packing goods and are thus very common in the food industry although not restricted to that field. The major advantages of containers are that they are easy to manufacture, cheap and are usually suitable for holding a variety of products. Such containers require minimal space in storage and are easily disposed of.
The most used form of container is the so-called "pouch" which is a sheet of material, e.g. paper, cardboard, plastic or a laminate formed into the shape of a bag or sack.
In some cases pouches are integrally formed with a base. However, such pouches are not self-standing and they require the internal pressure of their contents for stability. Furthermore, such pouches are usually oval and are thus less stable and also require more storage space. Still another drawback is that the structure of such products is not firm and thus they may collapse when they are not completely full.
In the present description and claims, the terms "heat weldable material" or "heat weldable surface" are used for determining layers of plastic material, e.g. polyethylene, polypropylene, etc. which, upon heating melt and may then be adhered to other such layers by a process which hereinafter in the specification will be referred to as "welding". The term "heat weldable" is also referred to in the art as "heat sealable".
Typical containers are made of a single sheet folded into a container's shape with overlapping portions which are then glued or welded to one another. Such containers are usually not suitable for containing liquids and do not have a rigid structure whereby they collapse when their contents are partially withdrawn. Furthermore, containers manufactured according to the heretofore known methods are usually restricted to pouch or prismatic box-like containers.
It is an object of the present invention to provide a novel and improved container and a process for manufacturing same in which the above-referred to disadvantages are substantially reduced or overcome.